1. Field of the Invention
The present invention relates to a damping circuit which is capable of damping a current oscillation caused across a coil when switching the coil for alternating a magnetizing direction of a magnetic body, and more particularly to the damping circuit which provides a technique for adjusting a magnitude of current flowing through a damping component.
2. Description of the Related Art
The inventors of the present application know the damping circuit, as shown in FIG. 2, which is arranged to have a coil 11, a first diode 15a, a second diode 15b, and a shunt resistor 13. Those two diodes 15a, 15b are connected in parallel to the coil 11 so that the first diode 15a may be directed in a reverse manner to the second diode 15b. The shunt resistor 13 is connected in series to both of these two diodes 15a, 15b. That is, the coil 11 is connected in parallel to the first diode 15a and the shunt resistor 13 connected in series to the first diode 15a as well as the second diode 15b directed reversely to the first diode 15a and the shunt resistor 13 connected to the second diode 15b.
When current flows from one terminal C to the other terminal D of the coil 11, counter electromotive force is caused between both of the terminals of the coil 11. The combination of the first diode 15a and the shunt resistor serves to damp the counter electromotive force caused by the current flowing in the direction. On the other hand, when current flows in an opposite manner, likewise, counter electromotive force is caused between both of the terminals of the coil 11. The combination of the second diode 15b and the shunt resistor 18 serves to damp the counter electromotive force caused by the current flowing in the opposite direction.
As described above, the known damping circuit uses those diodes for properly allowing or inhibiting the passage of current. However, the diode bridge circuit disables to adjust the current flowing through the shunt resistor. Therefore, the damping effect can not be improved.